Red Brook is a totally different experience, much more remote and pristine harbor. It's a place to be away from the crowds. Last time we were there we struck up a conversation with a cruising couple from Georgia who were hauled out for maintenance, and we invited them aboard for a pot-luck dinner. We bought some fresh-caught flounder from a guy on the dock who was cleaning his catch, topped it with salsa and broiled it in tin foil on the barbecue. They brought wine, and a side dish as I recall. A few glasses were raised and we made new friends.
Onset is a better stop for provisioning, dining and other connections ashore, and it's much faster in/out of the CC Canal. It too is a pretty harbor.